The Washington state-headquartered company, which Microsoft co-founder Paul Allen, set up in 2011, announced its latest vision for the Stratolaunch system on Aug. 20, 2018. The planned family of launch vehicles will include Orbital Sciences Corporation’s Pegasus XL, followed by a Medium Launch Vehicle (MLV), a more capable Medium Launch Vehicle-Heavy (MLV-H), and finally, a space plane known as “Black Ice.”

“We are excited to share for the first time some details about the development of our own, proprietary Stratolaunch launch vehicles, with which we will offer a flexible launch capability unlike any other,” Jean Floyd, Stratolaunch’s CEO, said in a press release. “Whatever the payload, whatever the orbit, getting your satellite into space will soon be as easy as booking an airline flight.”

Orbital Sciences Corporation, previously part of Orbital ATK and now part of Northrop Grumman, first successfully flew the Pegasus back in 1990 and introduced the XL model in 1994. Stratolaunch has long said that this would be one option for getting payloads into space via air launch from its own still-in-development mothership. Scaled Composites, which is building the aircraft, calls it the "Roc," after the mythological bird of prey that was said to be big enough to swoop down and carry away elephants.

Stratolaunch.

The Stratolaunch Roc while still under construction in 2017.

Pegasus XL can carry up to three payloads with a total weight of approximately 815 pounds and put them into a low earth orbit (LEO). Stratolaunch hopes to achieve the first flight of its carrier aircraft with one of these rockets in 2020. Stratolaunch says the Roc will be able to carry up to three of these rockets at once, making it an even more flexible launch option.

The MLV, which would hopefully make its first flight in 2022 and is also nicknamed “Kraken,” would offer more than nine times the payload capacity using a single rocket motor. The multi-motor MLV-H, which is reportedly in the early stages of development, would be able to lug payloads weighing approximately 13,220 pounds into LEO, or get a space-based system weighing up to 4,500 pounds into geostationary orbit.

Stratolaunch

An artist's conception of the MLV Kraken, at left, and the MLV-H, at right.

But the crown jewel of the Stratolaunch family is clearly the Black Ice space plane, which is presently just a design study. Unlikely the other three launch options, this vehicle would be able to not only go into space, but also come back and land like a regular airplane before getting prepped for another mission.

Stratolaunch says it plans for this vehicle to be “a fully reusable space plane that enables advanced in-orbit capabilities and cargo return. Initial designs optimized for cargo launch, with a follow-on variant capable of transporting crew,” according to the company’s press release.

Stratolaunch

An artist's conception of the Black Ice spaceplane.

If the company can make this work in a cost-effective manner, the entire family of vehicles could offer game-changing space-launch capabilities for both civilian and military applications. Just compared to typical satellite launches, a reliable, large capacity air-launched vehicle could give any customer a means of getting new payloads into orbit on short-notice. With satellites shrinking in size already, it is possible that the space plane, as well as the single-use MLV-H, could rapidly deploy multiple payloads at once, further reducing the cost of getting those payloads into space.

“I believe we’re going to be fighting from space in a matter of years,” U.S. Air Force Chief of Staff General David Goldfein said in February 2018. “And we are the service that must lead joint warfighting in this new contested domain. This is what the nation demands.”

The U.S. military has become steadily more aware of this issue, with the debate now centering around whether or not there is a need for a dedicated, separate military branch focused on space operations. At the same time, the U.S. Air Force and the Defense Advanced Research Projects Agency (DARPA) have already been actively looking into reusable space planes as a means to rush satellites into orbit as necessary and on short notice.

The video below offers an overview of DARPA's concept of operations for its experimental XS-1 space plane.

In its budget request for the 2019 Fiscal Year, the Air Force alone asked for more than $190 million to support a “small launch” program to explore ways of improving access to space, especially for light payloads. In the final defense spending bill for that fiscal cycle, which President Donald Trump signed into law earlier in August 2019, Congress demanded that the U.S. military as a whole consider at least one reusable launch option for getting any future space-based systems into orbit, as well as look into ways to expand cooperation with commercial firms on launches and operations in space.

Stratolaunch is clearly eager to position itself as a good option for anyone who needs to get payloads into position above the atmosphere quickly and without the need for costly and complex traditional rockets, launch sites, and associated infrastructure. The Roc will reportedly be able to launch its rockets at ranges up to 2,000 miles from where it took off and be able to rapidly stage from different locations.

The trick will be making the launches reliable enough to be routine and cost-effective enough to be a practical alternative to traditional space launch options. So far, the company has been tight-lipped about prospective costs. The six-engine, 500,000-pound mothership aircraft itself was originally set to cost around $300 million in 2011, but this had reportedly dropped to $200 million by 2016.

Burt Rutan, an aviation legend who has been in charge of the Roc design, initially thought he could build the plane for as little as $20 million, according to a profile of Stratolaunch that Wired just published on Aug. 20, 2018. He himself reportedly joked that the “Roc” name is just an acronym for “Rutan’s on Crack.” The aircraft has been performing various ground tests and its first flight could occur in 2019 or even earlier.

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The Roc during taxi tests in February 2018.

It’s not clear whether one aircraft will be able to provide the kind of scalable capacity that Stratolaunch would need to make the launches a routine affair. The cost to produce additional motherships and establish the necessary infrastructure to support them could have an impact on the final price per launch.

Stratolaunch’s CEO Floyd says Kraken MLV will be able to take payloads into LEO for $30 million or less, Wired reported, but it’s unclear what that figure includes. In 2015, NASA said that it would spend more than $56 million to launch an Ionospheric Connection Explorer (ICON) satellite, which weighs less than 700 pounds, using a Pegasus XL air-launched rocket and a different carrier aircraft. This included “firm-fixed launch service costs, spacecraft processing, payload integration, tracking, data and telemetry and other launch support requirements,” according to an official contract notice.

As of May 2018, SpaceX was reportedly offering launch services using its latest Block 5 Falcon 9 launch rocket, which can carry payloads weighing more than 50,000 pounds into LEO, starting at around $50 million, down from $62 million in 2016. DARPA’s goal for its XS-1 space plane, which Boeing is developing and will use a traditional rocket to get into space, is to be able to achieve a per-launch cost of just $5 million, but with a maximum of 3,000 pounds of payload.

Of course, Stratolaunch is targeting its launch vehicles at a different segment of the space launch market from SpaceX. If it can just keep pace with the price point of using traditional rockets at all, it might present a cost-effective option when factoring in the ability to conduct missions on much shorter notice. As noted, for the U.S. military, in particular, this will become an increasingly important capability to have available in the face of growing threats to space-based systems. China is notably also exploring aerial space launch capabilities for many of the same reasons.

SpaceX

A SpaceX Falcon 9 rocket sits on a launch pad.

There is a definite possibility the company may be able to leverage the U.S. government's increasing interest in public-private space partnerships to help further development of its various systems, as well. The company has already entered into an agreement where it will pay NASA more than $5 million to help develop the rocket motor for the MLVs.

If Stratolaunch can actually get the MLV launch cost down to around $30 million and make the other members of its launch vehicle family equally affordable for their respective capabilities, it could be a very exciting time for the space launch industry. But there’s still a lot of work left for the company to do to achieve its goals and the space plane, in particular, remains just a paper concept at present.